The processing of scrap incurred by dismounting or destroying already used objects and appliances, e.g., consumer scrap, constitutes a problem in the steel industry.
Consumer scrap, in particular motorcar scrap, is characterized by a high portion of organic impurities, such as combustible waste-like substances in solid or liquid forms, as well as nonferrous metallic accompanying substances and, therefore, can be processed at high expenditures only. At present, scrap usually is melted in electric arc furnaces, cupola and blast furnace hearths and in oxygen converters. However, for low-quality consumer scrap, only cupolas and blast furnaces are suitable.
A particular problem arises on account of the organic admixtures in the form of synthetic materials, which, upon heating, release offgases that are harmful to the environment and to health, containing dioxine, furan and higher hydrocarbons. Another problem is caused by the impurities, such as sulfur, which also constitutes a load on the environment together with the offgases.
A further problem is to be seen in that solid or liquid waste products formed by the meltdown process incur, part of which can be utilized only with difficulty or not at all such that they must be dumped anyway. Sulfur and chlorine-containing products constitute special waste, thus involving accordingly higher costs for dumping.